Imaging apparatus with selectable optical filters

ABSTRACT

An imaging box assembly is provided for capturing an image of a sample. The imaging box assembly includes a body having an interior cavity for receiving the sample, and having a front portion defining an opening into the cavity. The body further includes a view hole enabling viewing of the sample contained in the interior cavity. A door is mounted to the body that is movable between an opened condition, enabling access to the interior cavity through the cavity opening, and a closed condition, positioning a door rear portion substantially adjacent the body front portion to prevent access through the cavity opening. The box assembly further includes an optical filter select device to selectively position one of a plurality of optical filters between the sample and the view hole to intersect light from the sample.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 10/912,022, filed Aug. 4, 2004, by Michael D. Cable et al. andentitled, “Improved Imaging Apparatus,” now pending, the content ofwhich is hereby incorporated by reference herein, which in turn is adivisional application of U.S. application Ser. No. 09/795,056, filedFeb. 21, 2001 by Michael D. Cable et al. and entitled, “ImagingApparatus”, now issued as U.S. Pat. No. 6,775,567, the content of whichis hereby incorporated by reference herein, which claims the benefit of:U.S. Provisional Patent Application No. 60/184,859 filed Feb. 25, 2000,naming M. D. Cable et al. as inventors, and titled “Light-Tight SpecimenChamber”, which is incorporated by reference herein for all purposes.

FIELD OF THE INVENTION

The present invention relates generally to imaging systems. Morespecifically, the present invention relates to an imaging box whichforms part of an imaging system used for imaging low intensity lightsources, and also relates to numerous improvements to various componentsof an imaging box.

BACKGROUND OF THE INVENTION

One specialized type of imaging involves the capture of low intensitylight—on the order of individual photons—from a light emitting sample.The source of the light indicates portions of the sample where anactivity of interest may be taking place. For example, specializedin-vivo imaging applications may include analysis of one or morerepresentations of emissions from internal portions of a specimensuperimposed on a photographic representation of the specimen. Theluminescence representation indicates portions of the specimen where anactivity of interest may be taking place. The photographicrepresentation provides the user with a pictorial reference of thespecimen. Such imaging applications present particular challenges to thedesign of a box or chamber in which the sample is contained duringimaging.

One particular challenge to imaging box design is the diverse lightingneeds required during image capture. Photographic image capturetypically requires the sample to be illuminated. Luminescent imagecapture requires substantially no light other than minute amountsproduced within the sample. Conventional “light boxes”, or “specimenchambers” have thus been developed to maintain the sample being imagedin relative darkness during luminescent image capture.

FIG. 1A is a fragmentary, rear elevation view of the inside of alatchable door 1 of a conventional light box, as seen from the interiorof the box, showing a current latch mechanism 2. FIGS. 1B and 1Cillustrate a seal 4 situated between the door 1 of FIG. 1A and the frontwall of the box that the door is attached to. Collectively, the latchmechanism 2 and seal 4 allow a significant amount of light to enter thelight box.

Thus, conventional imaging boxes or specimen chambers may not beadequate for many imaging applications, e.g., when the imaging involvesthe capture of low intensity light on the order of individual photons.In view of the foregoing, improved imaging apparatus would be desirable.

SUMMARY OF THE INVENTION

The present invention relates to an improved imaging apparatus thatallow a user to perform numerous imaging operations. The presentinvention may include one or more improvements to imaging box design toimprove illumination control within the imaging box, such as improveddoor seal arrangements, improved door closing mechanisms, and improvedlight seals between housing surfaces. The present invention may alsoinclude one or more improvements to imaging apparatus design tofacilitate image capture, such as: an automated filter select device,automated focus control, f-stop adjustment and stage height, andimproved internal illumination for capturing photographic images.

In one aspect, the present invention provides a box or chamber devicethat is substantially more “light-tight” than conventional light boxes,and thereby allows for more sensitive and accurate detection and imagingof low intensity light sources. The present invention also provides avariety of new features and improvements to the light box andaccompanying imaging components to make the imaging process moreconvenient and accurate than was possible with “prior art” light boxes.

In another aspect, the present invention relates to an imaging box forcapturing an image of a sample. The imaging box comprises a bodyincluding an interior cavity for receiving the sample and having a frontwall defining an opening into the cavity. The imaging box also comprisesa door having a rear wall, the door movable between an opened condition,enabling access to the interior cavity through the cavity opening, and aclosed condition, positioning the rear wall substantially adjacent thebody front wall to prevent access through the cavity opening. The doorrear wall is adapted to cooperate with the front wall of the body, inthe closed condition, to define a capture space extending substantiallyperimetrically about the cavity opening. The imaging box furthercomprises a compressible material disposed at least partially within thecapture space, the compressible material having, when the door is in theclosed position, a first side compressed substantially uniformly by thedoor rear wall and a second side compressed substantially uniformly bythe front wall.

In still another aspect, the present invention relates to an imaging boxfor capturing an image of a sample. The imaging box comprises a bodyincluding an interior cavity for receiving the sample, and having afront wall defining an opening into the cavity, the front wall alsoincluding a first wall extending outward from the front wall. Theimaging box also comprises a door having a rear wall, the door movablebetween an opened condition, enabling access to the interior cavitythrough the cavity opening, and a closed condition, positioning the rearwall substantially adjacent the body front wall to prevent accessthrough the cavity opening. The door also including a second wall skewedtoward the front wall, the second wall adapted in a manner such that thesecond wall and the first wall substantially overlap, relative theirrespective depth, when the door is in the closed condition. The imagingbox further comprises a compressible material disposed at leastpartially between the first wall and the second wall.

In yet another aspect, the present invention relates to an imaging boxfor capturing an image of a sample. The image box comprises a bodyincluding an interior cavity for receiving the sample, and having afront wall defining an opening into the cavity. The image box alsocomprises a door having a rear wall, the door movable between an openedcondition, enabling access to the interior cavity through the cavityopening, and a closed condition, positioning the rear wall substantiallyadjacent the body front wall to prevent access through the cavityopening. The image box further comprises one of the body front wall andthe door rear wall including a pair of generally parallel channel wallsextending outwardly therefrom to form a channel extending substantiallyaround the perimeter of the interior cavity opening when the door is inthe closed condition. The image box additionally comprises acompressible material disposed in the channel. The image box alsocomprises the other of door rear wall and body front wall having aninterengaging wall extending outwardly therefrom and adapted to extendinto the channel in a manner such that the interengaging wall and thechannel walls substantially overlap, relative their respective depth,when the door is in the closed condition, the interengaging wall furtherengaging the compressible material such that light entering the channelfrom the exterior of the body is intercepted by compressible material.

In another aspect, the present invention relates to an imaging box forcapturing an image of a sample. The image box comprises a body includingan interior cavity for receiving the sample, and having a front walldefining an opening into the cavity. The image box also comprises a doorhaving a rear wall and an exterior face. The door movable is between anopened condition, enabling access to the interior cavity through thecavity opening, and a closed condition, positioning the rear wallsubstantially adjacent the body front wall to prevent access through thecavity opening. The image box further comprises a compressible materialdisposed on one of the rear wall and the front wall. The image boxadditionally comprises a first magnetic element attached to one of therear wall and the front wall, the first magnetic element providing afirst securing force between the door and the front wall when the dooris in the closed condition.

In still another aspect, the present invention relates to an imaging boxfor capturing an image of a sample. The image box comprises a bodyincluding an interior cavity for receiving the sample and having a frontwall defining an opening into the cavity. The image box also comprises adoor having a rear wall and an exterior face, the door movable betweenan opened condition, enabling access to the interior cavity through thecavity opening, and a closed condition, positioning the rear wallsubstantially adjacent the body front wall to prevent access through thecavity opening. The image box further comprises a compressible materialdisposed on one of the rear wall and the front wall. The image boxadditionally comprises a user handle on the exterior face of the door.The image box also comprises a first latch operably positioned by theuser handle and providing a securing force between the door and thefront wall at a first location. The image box additionally comprises asecond latch providing a securing force between the door and the frontwall at a second location.

In yet another aspect, the present invention relates to an imagingsystem for capturing an image of a sample. The imaging system comprisesan imaging box having a body including an interior cavity for receivingthe sample and having a front wall defining an opening into the cavity.The imaging box also having a door with a rear wall and an exteriorface, the door movable between an opened condition, enabling access tothe interior cavity through the cavity opening, and a closed condition,positioning the rear wall substantially adjacent the body front wall toprevent access through the cavity opening. The imaging system furthercomprises an optical filter select device adapted to carry a pluralityof optical filters, the filter select device capable of selectivelypositioning one of the plurality of optical filters to intersect lightemitted from the sample.

In another aspect, the present invention relates to an imaging systemfor capturing an image of a sample. The imaging system comprises animaging box having a body including an interior cavity for receiving thesample and a front wall defining an opening into the cavity. The imagingsystem also comprises a door having a rear wall and an exterior face.The door movable between an opened condition, enabling access to theinterior cavity through the cavity opening, and a closed condition,positioning the rear wall substantially adjacent the body front wall toprevent access through the cavity opening. The imaging system furthercomprises a moveable stage in the cavity interior that supports thesample, the moveable stage having a first vertical position and a secondvertical position in the interior cavity, wherein the first verticalposition and the second vertical position have the substantially samehorizontal position in the interior cavity.

In still another aspect, the present invention relates to an imagingsystem for capturing an image of a sample. The imaging system comprisesan imaging box having a body including an interior cavity for receivingthe sample, and having a front wall defining an opening into the cavity.The imaging system also comprises a door having a rear wall and anexterior face, the door movable between an opened condition, enablingaccess to the interior cavity through the cavity opening, and a closedcondition, positioning the rear wall substantially adjacent the bodyfront wall to prevent access through the cavity opening. The imagingsystem further comprises a stage in the cavity interior configured tosupport the sample. The imaging system additionally comprises a gasmanifold in the cavity interior and detachably coupled to the stage, themanifold including a first interface adapted to provide a gas to thesample. The imaging system also comprises a tube configured to transportthe gas from outside the imaging box to the gas manifold.

In yet another aspect, the present invention relates to an imaging boxfor capturing an image of a sample. The image box comprises a bodyincluding an interior cavity for receiving the sample, and having afront wall defining an opening into the cavity. The image box alsocomprises a door having a rear wall, the door movable between an openedcondition, enabling access to the interior cavity through the cavityopening, and a closed condition, positioning the rear wall substantiallyadjacent the body front wall to prevent access through the cavityopening. The image box further comprises at least one light tight seal,the seal comprising a first surface including a first channel, a secondsurface including a second channel, the first surface opposing thesecond surface such that the first channel and second channel at leastpartially face each other, and a compressible gasket disposed in thefirst and second channel, the gasket configured to contact opposingedges of the first and second channel when the first and second surfacesare in contact.

These and other features of the present invention will be described inmore detail below in the detailed description of the invention and inconjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1A is a rear elevation view of the inside of a latchable door of aconventional light box, as seen from the interior of the box, showing acurrent latch mechanism.

FIG. 1B is an enlarged perspective view, partially broken away, of aconventional seal used in the light box of FIG. 1A.

FIG. 1C is a top plan view, in cross-section of the conventional seal ofFIG. 1B.

FIG. 1D is an enlarged, cross-sectional view of a conventional sealbetween two surfaces.

FIG. 2 is a perspective view of an imaging system including an imagingbox, in accordance with one embodiment of the present invention.

FIG. 3 is a perspective view of the imaging box and some attachedimaging components of FIG. 2, with the imaging box door open and itselectronics drawer pulled out.

FIG. 4 is a front perspective view of part of the imaging box of FIG. 2with a portion of the door cut away, illustrating a sealing arrangementin accordance with one embodiment of the invention.

FIGS. 5A, 5B, 5C and 5D are cross-sectional views of parts of the doorand front wall of the imaging box of FIG. 2, illustrating sealingarrangements in accordance with various embodiments of the invention.

FIGS. 6A, 6B, 6C and 6D are fragmentary rear elevation views thatillustrate the inside of the door, as seen from the interior of theimaging box of FIG. 2, showing latch mechanisms in accordance withvarious embodiments of the present invention.

FIG. 6E illustrates a magnetic latch mechanism for securing the door ofFIG. 2 in accordance with another embodiment of the present invention.

FIG. 7 is a perspective view of the imaging box of FIG. 2 with its dooropen, showing a uniform pressure applying mechanism, in accordance withanother embodiment of the present invention.

FIG. 8 is a fragmentary cross-sectional view of the door of the imagingbox of FIG. 7, illustrating a portion of the uniform pressure applyingmechanism in accordance with one embodiment of the present invention.

FIG. 9 is a bottom plan view, cut-away, of the imaging box of FIG. 2,illustrating various imaging components in accordance with oneembodiment of the present invention.

FIG. 10 is a perspective view of selected imaging components included inthe imaging box of FIG. 2 in accordance with one embodiment of thepresent invention.

FIG. 11 is a front elevation view, in cross-section, of the interior ofthe imaging box of FIG. 2 and associated imaging components.

FIG. 12 is a bottom perspective view of the interior of the imaging boxof FIG. 2, with portions cut away, showing various features of the boxand associated imaging components.

FIG. 13 is a perspective view of the moveable stage of the imaging boxof FIG. 2 showing an integrated heating element in accordance with oneembodiment of the present invention.

FIGS. 13B-C are side and top views, respectively, of a gas deliverysystem comprising a gas manifold detachably coupled to the moveablestage of the imaging box of FIG. 2 in in accordance with one embodimentof the present invention.

FIG. 14A is a top view of a light source mounted in the imaging box ofFIG. 2 according to one embodiment of the invention.

FIG. 14B is a top view of a light source mounted in the imaging box ofFIG. 2 according to another embodiment of the invention.

FIG. 15 is a cross-sectional view of an “o-ring” light-seal according toanother embodiment of the invention.

FIG. 16 is a perspective view of the electronic component drawer of theimaging box of FIG. 2 in accordance with one embodiment of the presentinvention.

FIG. 17 is a flow chart illustrating a method of capturing photographicand luminescence images using the imaging box of FIG. 2 in accordancewith embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description of the present invention, numerousspecific embodiments are set forth in order to provide a thoroughunderstanding of the invention. However, as will be apparent to thoseskilled in the art, the present invention may be practiced without thesespecific details or by using alternate elements or processes. In otherinstances well known processes, components, and designs have not beendescribed in detail so as not to unnecessarily obscure aspects of thepresent invention.

I. Imaging System

In one aspect, the present invention relates generally to improvedimaging systems. FIG. 2 illustrates an imaging system 10 configured tocapture photographic and luminescence images in accordance with oneembodiment of the present invention. The imaging system 10 may be usedfor imaging a low intensity light source, such as luminescence fromluciferase-expressing cells, fluorescence from fluorescing molecules,and the like. The low intensity light source may be emitted from any ofa variety of light-emitting samples which may include, for example,tissue culture plates, multi-well plates (including 96, 384 and 864 wellplates), and animals or plants containing light-emitting molecules, suchas various mammalian subjects such as mice containing luciferaseexpressing cells.

The imaging system 10 comprises an imaging box 12 adapted to receive alight-emitting sample in which low intensity light, e.g.,luciferase-based luminescence, is to be detected. The imaging box 12includes an upper housing 16 in which a camera lens is mounted. A highsensitivity camera, e.g., an intensified or a charge-coupled device(CCD) camera 20 is positioned on top of the imaging box 13 andpositioned above, the upper housing 16. The CCD camera 20 is capable ofcapturing luminescent and photographic (i.e., reflection based images)images of the sample within the imaging box 12. The CCD camera 20 iscooled by a suitable source such as a refrigeration device 22 thatcycles a cryogenic fluid through the CCD camera via conduits 24. Asuitable refrigeration device is the “CRYOTIGER” compressor, which canbe obtained from IGC-APD Cryogenics Inc., Allentown, Pa. Other methods,such as liquid nitrogen, may be used to cool the CCD camera 20.

An image processing unit 26 optionally interfaces between camera 20 anda computer 28 through cables 30 and 32 respectively. The computer 28,which may be of any suitable type, typically comprises a main unit 36that typically contains hardware including a processor, memorycomponents such as random-access memory (RAM) and read-only memory(ROM), and disk drive components (e.g., hard drive, CD, floppy drive,etc.). The computer 28 also includes a display 38 and input devices suchas a keyboard 40 and mouse 42. The computer 28 is in communication withvarious components in the imaging box 12 via cable 34. To providecommunication and control for these components, the computer 28 includessuitable processing hardware and software configured to provide outputfor controlling any of the devices in the imaging box 12. The processinghardware and software may include an I/O card, control logic forcontrolling any of the components of the imaging system 10, and asuitable graphical user interface for the imaging system 10. Thecomputer 28 may also includes suitable processing hardware and softwarefor the camera 20 such as additional imaging hardware, software, andimage processing logic for processing information obtained by the camera20. Components controlled by the computer 28 may include the camera 20,the motors responsible for camera 20 focus, the motors responsible forposition control of a platform supporting the sample, the camera lens,f-stop, etc. The logic in computer 28 may take the form of software,hardware or a combination thereof. The computer 28 also communicateswith a display 38 for presenting imaging information to the user. By wayof example, the display 38 may be a monitor, which presents an imagemeasurement graphical user interface (GUI) that allows the user to viewimaging results and also acts an interface to control the imaging system10.

A. Imaging Box

In one aspect, the present invention relates to an imaging box suitablefor various imaging operations. FIG. 3 illustrates the imaging box 12 ofFIG. 2 in accordance with one embodiment of the present invention. Theimaging box 12 is suitable for imaging including the capture of lowintensity light on the order of individual photons, for example. Theimaging box 12 substantially improves the control of imaging performedtherein and is designed to improve the quality of the images generatedfrom extremely low levels of light. In one embodiment, the imaging box12 the quality of imaging by preventing the entry by light external tothe imaging box in the ambient room. The imaging box 12 is referred toas “light-tight”, e.g., it seals out essentially all of the externallight from the ambient room from entering the box 12. The term“light-tight box” as used herein means a box or chamber device thatseals out essentially all of the external light that would otherwiseenter the box.

As shown in FIG. 3, the imaging box 12 includes a number of adaptationsin accordance with the present invention. The imaging box 12 isillustrated with its door 18 open, showing an interior cavity 44 forreceiving the sample. The interior cavity 44 is defined by opposing sideenclosure panels 45 a and 45 b (45 b not visible in FIG. 3), alight-tight partition 52 on the bottom, a top partition 103 (FIG. 10), aback enclosure panel 47, and a front wall 48 defining a cavity opening49 into the interior cavity 44. Below the cavity 44 is a smallercompartment separated therefrom by the light-tight partition 52, theupper surface of which serves as a floor for the cavity 44. In oneembodiment, the smaller compartment acts as a housing space and isadapted to slideably receive a drawer 54 though a front opening 55formed in the body 14. The drawer 54 houses electronic components 56which are in electrical communication with the computer 28 (FIG. 2) andcontrol various components and functions of the box 14. In anotherembodiment, the imaging box 12 has a body 14 made of a suitable metalsuch as steel.

A latchable door 18 is pivotally attached to box body 14 by way ofhinges 46 which permit the door 18 to be moved from the closed positionas shown in FIG. 2 to the open position as shown in FIG. 3. In the openposition, the door 18 enables user access to the cavity 44 through theopening 55. In the closed position, where an inside wall of the door 18is substantially adjacent to the body front wall 48, the door 18 preventaccess to the cavity interior 44 through the cavity opening 55. Althoughthe hinges 46 may be of any suitable design, they are generallydesigned, made and installed to enable the door 18 to close properly toprovide the required sealing characteristics, as will be explainedbelow. In addition, although the imaging box is illustrated anddiscussed with only one door 18 for sake of brevity, the imaging box maycomprise two or more doors for access to the interior cavity 44.

The body front wall 48 defines the cavity opening 49 to the interiorcavity 44. Around the perimeter of the cavity opening 49, extendingoutwardly, generally perpendicular to front wall 48, is a second wall50. In one embodiment, the second wall 50 extends substantiallyperimetrically around the cavity opening 49. The second wall 50 includesa distal edge portion positioned substantially adjacent the door rearwall when the door 18 is in the closed position. As will be explained inseveral embodiments below, the walls 48 and 50 cooperate with walls ondoor 18 to form a capture space around the perimeter of the cavityopening 49. This capture space substantially minimizes the amount ofexternal light that can enter the cavity 44 when the door 18 is closed.

As shown in FIG. 3, the door 18 carries a latch mechanism 60 forsecuring the door 18 in the closed position. The door 18 also includes acompressible material 62 attached thereto for preventing lightpenetration by light in the ambient room. Thus, when the door 18 isclosed and secured, a seal formed by cooperation between the door 18 andthe body 14 creates a substantially “light-tight” seal for the cavity44.

FIGS. 4, 5A, 5B, 5C and 5D illustrate different embodiments of alight-tight seal formed by cooperation between the door 18 and the body14 in accordance with various embodiments of the present invention. Eachof the seals 61 a, 61 b, 61 c and 61 d in FIGS. 5A, 5B, 5C and 5D,respectively, may include the compressible material 62. In oneembodiment, the compressible material 62 is non-transparent, preferablyblack, and made from a resiliently deformable material. In a specificembodiment, the compressible material 62 is an elastomer having amodulus of elasticity of less than about 1000 psi. Preferably, thecompressible material's modulus of elasticity is less than about 200psi, and more preferably is less than about 100 psi. In anotherembodiment, the material has a durometer rating of between about 10 andabout 50, and preferably between about 20 and 30.

FIGS. 4 and 5A illustrate a light-tight seal 61 a between the door 18and the body 14 walls 48 and 50 in accordance with one embodiment of thepresent invention. As shown, door 18 comprises a front wall 64, a rearwall 70, a side wall 66 and a second wall segment 68. The rear wall 70is attached to the inner surface of the door front wall 64. In aspecific embodiment, door rear wall 70 has a wall section 71 thatextends substantially perimetrically around the cavity opening 49 whenthe door 18 is in the closed position. In another embodiment, the wallsection 71 extends toward the body front wall 48 at an orientationengaging a fourth side portion 63 d of the compressible material 62between a second side portion 63 b thereof engaged by the body frontwall 48 and a first side portion 63 a of the compressible material 62engaged by the door rear wall 70.

As shown in FIGS. 4 and 5A, door walls 66, 68 and 70 cooperate withexternal surfaces on box walls 48 and 50 to define a capture space 72.Generally, the door 18 and box walls 48 and 50 may be arranged to formthe capture space 72 having any polygonal cross-section. In this case,the capture space 72 has a rectangular cross-sectional area, as shown inFIGS. 4 and 5A, where a vertex A formed by box walls 48 and 50 opposes avertex B formed by door walls 64 and 66.

The compressible material 62 is preferably disposed at least partiallyin the capture space 72 and compressed therein. In one embodiment, thecompressible material 62 has a transverse cross-sectional dimensioncompressed at least partially by the body front wall 48 and at leastpartially by the door rear wall 70 when the door 18 is in the closedposition. The door rear wall 70 is adapted to compress the compressiblematerial 62 substantially along the entire first side portion 63 a ofthe compressible material 62, and the body front wall 48 is adapted tocompress the compressible material 62 substantially along the entiresecond side portion 63 b, when the door 18 is in the closed position.Consequently, light entering the capture space from the exterior of thebox 12 is intercepted by compressible material 62. In this case, thesides of the compressible material 62 being compressed by the door 18and body 14 are positioned on opposite sides of the compressiblematerial 62. It should be noted that the walls defining the capturespace 72 may compress more than two sides of the compressible material62. By way of example, the second wall 50 extending from the body frontwall 48 is adapted to engage a third side portion 63 c of thecompressible material 62 extending between the first side portion 63 aand the second side portion 63 b.

In one embodiment, the capture space 72 and compressible material 62both extend substantially perimetrically about the cavity opening 49.For example, in FIG. 5A, the dimensions and compressibility of thecompressible material 62 are selected such that, when the door isclosed, (i) each portion of the material 62 that contacts a door or boxwall (i.e., box wall 48, second wall 50, and door rear wall 70) iscompressed substantially uniformly along its contact portion, and (ii)there is a relatively small gap G between door wall 68 and front wall48, such that the force exerted by the latch mechanism to retain thedoor 18 in the closed position is a consequence of contact with thecompressible material 62 and not by contact between the door 18 and thebox 12. The small gap G is provided by the compressible material 62which is sized and dimensioned to prevent the door rear wall 70 fromcontacting the front wall 50 when the door 18 is in the closedcondition.

The light seal 61 is thus formed by the material 62 pressing against oneor more planar surfaces of the door 18 and body 14, thereby compressingsubstantially the entire perimetric sealing surface between the door 18and the front wall 48 of the box 12. Accordingly, the door rear wall 70and the body front wall 48 cooperate with the compressible material 62to provide a light seal that causes light entering the capture space 72to traverse the transverse the cross section of the material 62 forinterception of the light thereof. The seal 61 a thus greatly minimizeslight penetration resulting from any interruptions in perimeter contactbetween the wall 50 and material 62 a when the door 18 is closed.

Referring back to FIG. 1C, experimentation performed by the applicantssuggests that the seal 4 can be traversed by light making only slightdeflections from a straight path. Accordingly, any defects in the seal 4along its length can result in a significant amount of light enteringthe box.

To further reduce light penetration, the capture space 72 of FIG. 5Aintroduces two right angles that light would need to negotiate before itcould enter the interior cavity 44 from the outside. Any light passingbetween front wall 48 and second wall segment 68 would thus be requiredto traverse at least two right angle turns before reaching the interiorside of wall 50. Moreover, since the compressible material 62 is alsopreferably disposed at these right angle turns, such light would beintercepted by the disposed material. This design thereforeadvantageously improves the light barrier between the cavity 44 and theambient room.

In the embodiment illustrated in FIGS. 4 and 5A, the compressiblematerial 62 a is rectangular-shaped in cross-section (e.g., about 0.75in. by 0.5 in.) and has a solid core. By way of example, thecompressible material 62 may be made of an adhesive backed closed cellfoam having a density of between about 7 to about 9 lbs./cu. ft. and acompressibility of about 25% deflection at 5 to 9 psi. Typical of suchmaterials is produced by Rogers of Decatur, Ill. In another embodiment,the material 62 b is opaque with a light absorbing surface.

In addition to the light barrier provided by the capture space 72 andthe compressible material 62 a, the door side wall 66 and second wallsegment 68 also function to prevent light penetration into the interiorcavity 44. The side wall 66 is attached to the front wall 64 of the doorand extends outwardly therefrom toward the body front wall 48. The sidewall 66 is skewed toward the front wall 48 of the box 12 and is adaptedsuch that the side wall 66 substantially overlaps the second wall 50relative their respective depths when the door 18 is closed. Thus, adistal edge portion of the second wall 50 is positioned substantiallyadjacent the door rear wall 70, and a distal edge portion of the doorside wall 66 is positioned substantially adjacent the body front wall48. Preferably, the side wall 66 extends substantially perimetricallyaround the opening 49 and substantially perimetrically outside andgenerally parallel to the second wall 50 when the door 18 is in theclosed position. In another embodiment, the side wall 66 extends towardand substantially perpendicular to the box front wall 48 when the door18 is closed.

Extending from the distal portion of the side wall 66 is the second wallsegment 68 which is also substantially adjacent and preferably parallelto the body front wall 48 as shown in FIG. 5A As previously indicated,the compressible material 62 is sized to create a relatively small gap Gbetween the distal edge portion of side wall 66 and front wall 48 whichprevents the door rear wall 70 from contacting the front wall 50 whenthe door 18 is in the closed condition. In one embodiment, this gap G isin the range of about 1/1000 inches to about 1/2 inches. In a morespecific embodiment, the small gap G is in the range of about 1/1000inches to about 1/8 inches.

Referring now to FIG. 5B, a light-tight seal 61 b is formed between thedoor 18 and the body 14 walls 48 and 50 in accordance with anotherembodiment of the present invention. In this embodiment, thecompressible material 62 b is also disposed in the capture space 72(formed by walls 48, 50, 70 and 71). Similar to the embodiment of FIG.5A, the compressible material is compressed along its opposite sides 63b and 63 a by walls 48 and 70, respectively. In addition, thecompressible material 62 b includes a ledge portion 76 which protrudesbetween the distal portion of box second wall 50 and the door wall 70 toextend into the box cavity 44 when the door 18 is in the closedposition. In this case, the second wall 50 is shortened and its distalportion compresses the ledge portion 76 outside the capture space 72 toprovide additional light sealing. More specifically, upon closing thedoor 18, the ledge portion 76 is compressed by the distal portion of boxwall 50 and door wall 70. The material 62 b with its custom profile maybe custom-made by a suitable seal or gasket manufacturer such as EPM,Inc., Stockbridge, Ga. In one embodiment, the material 62 b is made ofsolid rubber having a durometer between about 20 and about 30, such asethylene propylene diene monomer (EPDM) or styrene-butadiene rubber(SBR).

FIG. 5C illustrates yet another light-tight seal 61 c in accordance withanother embodiment of the present invention. The seal 61 c includes achannel 75 formed by generally parallel channel walls 78 and 79 whichextend outwardly from the door 18 toward the box front wall 48, andfurther extend perimetrically about the cavity opening 49 when the door18 is in the closed condition. A compressible material 62 c is disposedin the channel 75. The box second wall 50, extending outwardly from thefront wall 48, is adapted to extend into the channel 75 in a manner suchthat the second wall 50 and the channel walls 78 and 79 substantiallyoverlap, relative their respective depth, when the door 18 is in theclosed condition. In addition, the channel walls 78 and 79 and theinterengaging second wall 50 are, preferably substantially parallel toone another when the door 18 is in the closed condition.

In one embodiment, the dimensions and compressibility of thecompressible material 62 c of FIG. 5C are selected such that, when thedoor 18 is closed and latched, the material 62 c is relatively uniformlycompressed around the perimeter of the cavity opening 49 when the distalportion of the box second wall 50 contacts the material. Further, thecompressible material is sized to form the small gap G between door wall68 and front wall 48, such that the force exerted by the latch mechanismto retain the door 18 in the closed position is dispersed by thematerial 62 c. In this case, the light seal 61 c is formed when thedistal portion of the box wall 50 compresses the material against thedoor wall 70. As a result, the geometry of the overlap requires lightentering the channel 75 from the exterior of the body 14 to beintercepted by the compressible material 62 c. In one embodiment, thecompressible material 62 c has a thickness of at most ¾ of the depth ofthe channel 75, and preferably at most ½ of the depth of the channel 75.

It should be noted that in the structural arrangement of FIG. 5C, alight-tight seal may still be formed without the compressible material62 c. This is due to the geometry of the spaced-apart channel walls 78,79 and the interengaged second wall 50, and their spatial relationships,in the closed position. Any ambient light entering through Gap G mustnegotiate the maze formed between these interengaged walls. As viewed inFIG. 5C, such diffused light must traverse at least three right angleturns created by the walls before it can enter the interior cavity 44.

Although the channel walls 78 and 79 are on the door 18 and theinterengaging second wall 50 is on the opposing front wall 48, it willbe understood that the channel walls may be placed on the front wall 48and the opposing interengaging wall situated on the door 18. Further, itwill be appreciated that the seal 61 according to the present inventionmay contain two or more such channels and interengaging walls to improvelight protection for the interior cavity 44.

FIG. 5D illustrates such a light-tight seal 61 d which includes firstand second compressible materials 62 d and 62 e, retained inside twochannels 77 a and 77 b, respectively. The channel 77 a is formed bychannel walls 78 and 79, both of which extend from the door 18 similarto the light-tight seal 61 c. The channel 77 b is formed by generallyparallel channel walls 50 a and 50 b, both of which extend from thefront wall 48 of the box 12 and substantially perimetrically around thecavity opening 49. In this case, the channel wall 79 is received in thechannel 77 b when the door 18 is in the closed condition. Thus, thechannel wall 79 engages the second compressible material 62 e such thatlight entering the second channel 77 b from the exterior of the body 14is intercepted by the second compressible material 62 e.

The materials 62 d and 62 e fill only a portion of the channels 77 a and77 b respectively, e.g., at most about ¾ of the channel 75 depth asmeasured from the walls 70 and 48 respectively, preferably at most about½ the channel depth, and more preferably at most about ¼ the channeldepth. Thus, the interengaged walls 50 a and 50 b and channel walls 78and 79 substantial overlap, relative their respective depth, when thedoor 18 is closed. Any light attempting to penetrate the light barrierwould require at least six right angle turns (including four through thecompressible materials 62 d and 62 e) before it can enter the interiorcavity 44 from the ambient room.

Similar to the embodiments illustrated in FIGS. 5A and 5B, the door 18of FIGS. 5C and 5D further includes door side wall 66 extendingoutwardly from the door 18 toward the front wall 48 when the door is inthe closed position. In this case, the door side wall 66 is positionedperimetrically outside and generally parallel to the channel walls 78and 79 and the interengaging front wall 50. The door 18 further includesthe second wall segment 68 extending from the door side wall 66, andoriented substantially adjacent to the front wall 48 when the door 18 isin the closed condition. As shown, the second wall segment 68 extends inthe inward direction toward interengaging front wall 50 and the channelwalls 78 and 79.

In another aspect of the present invention, several designs for securingthe door 18 are provided that minimize light penetration from theambient room. Referring back to FIGS. 1A-C, experimentation performed bythe applicants suggests that the securing force provided by the latchmechanism 2 when the door 1 is closed may also lead to additionalundesired light entering the box. When the door 1 is closed, the latchmechanism 2 provides a localized securing force at a single point alongthe door 1 (i.e., at the point of contact between the latch mechanism 2and the door 1). This localized force provides an inconsistent pressurealong the seal 4 and may lead to gaps in the seal 4 and other lightsealing inconsistencies around the perimeter of the box 12.

As shown in FIGS. 6A-6D, latch mechanisms 60 a-d for securing the door18 in accordance with various embodiments of the present invention. Thelatch mechanisms 60 a-d include multiple points of contact between thedoor 18 and the box 12 to provide more uniform force distribution acrossfor the seal 61. This more uniform distribution minimizes lightpenetration resulting from any inconsistencies in perimeter contactbetween the wall 50 and material 62 when the door 18 is closed.

FIGS. 3 and 6A illustrate the latch mechanism 60 a in accordance withone embodiment of the present invention. The latch mechanism 60 aincludes a plurality of latches 86 located on the inside of the door 18.Each latch 86 is moveable between a first position, disengaged with thefront wall 48, and a second position, engaged with the front wall 48 inwhich a securing force is applied between the door 18 and the front wall48 at a strategic location. Together, the latches 86 provide amulti-point seal between the compressible material 62 in the door 18 andbox walls 48 and 50 and distribute the applied compressive closing forcealong the vertical non-hinged edge 81 of the door. This multiple contactprovides a substantially uniform securing and compression force againstthe compressible material 62 and along the vertical non-hinged edge 81between the latches 86.

The latch mechanism 60 a includes a main latch 80 and two dependentlatches 82, each of which is moveably linked to the main latch 80 byrods 84. The rods 84 are each slideably supported by stays 86 which aremounted to the rear wall 70 of the door 18. The main latch includes alatch element 88 rotatably mounted on the inside of the door 18 forapplying a force against the box 12. A handle 90 (see FIG. 2) extendsfrom the exterior face of the door 18 to enable user manipulation. Thehandle 90 permits a user to operably position the latch element 88 andeach of the dependent latches 82 between the first position, where thelatches are disengaged with the inner surface of wall 48 (solid lines inFIG. 6A), and the second position, where the latches are engaged (brokenlines in FIG. 6A). In one embodiment, the latch element 88 and dependentlatches 82 may have a tapered engaging surface that contacts the wall 48and provides a controllable amount of force which increases as therotation of the handle 90 increases. In another embodiment, the mainlatch does not include a latch element 88 and the dependent latches 82each comprise a rectangular element that applies the securing forcebetween the door 18 and the box 12. Such a configuration is commerciallyavailable from Doortronics Systems, Inc. of Sag Harbor, N.Y.

FIG. 6B illustrates another latch mechanism 60 b in accordance with oneembodiment of the present invention. The latch mechanism 60 b includes aplurality of spaced-apart latches 82 disposed along the inside of thedoor 18 to provide a multi-point seal against the compressible material62 between the door 18 and box walls 48 and 50. This arrangementuniformly distributes the compressive force when the door 18 is closedsubstantially about the perimeter of the box opening 49. This isperformed by providing four dependent latches 82 a distributed on fourdifferent edges of the door. Each dependent latch 82 a is moveablylinked by individual rods 84 a to a cam device 80 a which is rotatablymounted to the center of the door 18. These rods 84 a are each slideablysupported by stays 86 a mounted to the inside of the door 18. With thisarrangement, the cam device 80 a does not have a latch element thatengages to the box 12, such as the latch element 88 of the embodiment ofFIG. 6A An external knob, however, is included for user manipulation andsimultaneously actuating the four dependent latches 82 between engagedand disengaged positions. In one embodiment, the dependent latches 82may have a tapered engaging surface that contacts the wall 48 in orderto provide a controllable amount of force when securing the door 18.

Referring now to FIGS. 6C and 6D, latch mechanisms 60 c and 60 d areillustrated in accordance with other embodiments of the presentinvention. In both embodiments, at least three latches 80 b and 80 c,respectively, are provided, each with their own independentlycontrollable external handle. These latches are spaced-apart atstrategic locations about perimeter of the door 18 and box opening 49.Each latch 88 b, 88 c is moveable between a first position, disengagedwith the front wall 48 (solid lines in FIGS. 6C and 6D), and a secondposition, engaged with the front wall 48 in which a securing force isapplied between the door 18 and the front wall 48 (broken lines in FIGS.6C and 6D). In the latch mechanism 60 c embodiment, the latches 88 b arespaced-apart along the vertical edge 81 of the door opposite the doorhinges. Collectively, the latches 88 provide securing forces whichuniformly compress the compressible material 62 substantially betweeneach pair of latches 88 along the vertical edge 81 of the door 18. Inthe latch mechanism 60 d embodiment, in contrast, the latches 88 c arespaced-apart along different door 18 edges. Each latch 88 c is equippedwith its own user handle to operably position its corresponding latch 88between the disengaged first position (solid lines in FIG. 6D), and theengaged second position (broken lines in FIG. 6D). Similarly, the latchelement may have a tapered engaging surface which provides acontrollable amount of force which increases with increased rotation ofits external knob.

FIG. 6E illustrates a latch mechanism 180 for securing the door 18 ofFIG. 2 in accordance with another embodiment of the present invention.The latch mechanism 180 includes a magnetic element 182 attached to thebox 12 front wall. The magnetic element 182 provides a securing forcebetween the metal door 18 and the front wall when the door 18 is in theclosed condition. In a specific embodiment, the magnetic element 182 isa permanent magnet that provides a securing force large enough tocompress the compressible material 62 and to keep the door frominadvertently opening when someone brushes the door 18 or other similarsmall forces that may open the door 18. In a specific embodiment, themagnetic element 182 is a permanent magnet that generates a securingforce in the range of 25-30 lbf. In another embodiment, the latchmechanism 180 includes a second magnetic element, similar to themagnetic element 182, attached to the box 12 front wall at another pointon the box 12 face. Together, the two magnetic elements provide amulti-location closing mechanism that distributes the appliedcompressive closing forces along the perimeter of the door 18. Thismulti-location magnetic latch provides a substantially uniform securingand compression force against the compressible material 62 and along thedoor 18 between the magnetic elements.

In another embodiment, the latch mechanism 180 includes an electromagnet183 a and 183 b attached on facing surfaces of the door 18 and the box12 front wall. The electromagnet 183 provides a securing force betweenthe metal door 18 and the front wall when the door 18 is in the closedcondition. The securing force provided by the electromagnet 183 is largeenough to keep a user from opening the door 18. In a specificembodiment, the electromagnet is only powered during luminescent imagecapture of the sample, thus preventing the door 18 to be accidentally orinadvertently opened during luminescent image capture.

FIGS. 7 and 8 illustrate a mechanism for securing the door 18 inaccordance with another embodiment of the present invention. A pluralityof screw latches 92 are spaced about the perimeter of the door 18 andconfigured to engage with corresponding threads 94 in wall 48 of the box12. When the door 18 is in the closed position, the screw latches 92contact their corresponding threads 94. Each screw 92 is then driven byan individual worm-drive stepper motor 96 to apply a predeterminedamount of pressure to the compressive material 62 disposed between thedoor 18 and the wall 48A pressure transducer 98 communicates with eachmotor 96 and is programmed to stop the motor when the predeterminedamount of pressure is reached. The transducers 98 may be coupled to thecomputer 28, and may be, programmed to be conveniently adjust theproperties thereof through keyboard 40 and/or mouse 42.

Advantageously, the design of the seal 61 and the distributed manner inwhich the seal 61 is engaged when the door 18 is closed provide asubstantially more light-tight imaging box than was previouslyavailable, as evidenced by the comparison testing described below.Having briefly discussed various illumination control improvements ofthe imaging box 12, numerous other aspects of the imaging box 12 willnow be discussed.

Referring now primarily to FIGS. 9, 10 and 11, various components housedin the upper portion of the box 12 will now be detailed. FIG. 9 is abottom view of the components in the upper portion of the box 12 withthe top face of the box 12 cut away. FIG. 10 is a perspective view ofselected imaging components in the upper portion of the box 12. FIG. 11is a cross-sectional side view of the box 12 looking into the cavity 44with various components in the upper portion of the box 12 shown incross-section.

The system 10 provides user automated control of image capture in thebox 12. Referring to FIGS. 9 and 11, a camera lens 100 is mounted inupper housing 16, with the lens 100 in view of the interior cavity 44through a hole 101 formed in a top plate 103 of the box 12. The cameralens 100 is optically coupled to the camera 20 of FIG. 3. and includes auser controlled aperture or F-stop ring 102 for adjusting the F-stop oraperture of the lens 100, thereby modulating the amount of light passingthrough the lens. By way of example, a Navitar, f 0.95, 50 mm TV lens issuitable for use as the camera lens 100. The F-stop ring 102 includescircumferentially disposed teeth that engage a gear 104 driven by anF-stop motor 106. The F-stop motor 106 is in electrical communicationwith the electrical components 56 and controlled by computer 28.Together, the motor 106 and processor in computer 28 act to position thef-stop of the lens 100.

Also associated with the camera lens 100 is a focusing mechanismincluding lens support 107 for supporting and focusing the lens 100 toprovide reciprocal movement thereof. The lens support 107 includes astationary portion mounted to upper housing 16 and a movable portionthat includes a threaded bore 109. A bolt 108, operably engageable withthe bore 109, includes a wheel that is driven by a toothed belt 110through a corresponding drive wheel 112 of a camera lens focus motor 114to move the camera lens 100 into focus. The camera lens focus motor 114is in electrical communication with the electrical components 56 andcontrolled by a processor included in computer 28.

In addition to automated focus control of the camera lens 100, thesystem 10 also includes an automated filter select device 117 capable ofselectively providing multiple filters 118 at least partially betweenthe camera 20 and the sample. The filters 118 may each facilitate imagecapture for one or more particular imaging applications. As shown inFIGS. 9 and 11, the optical filter select device 117 includes a circularfilter select wheel 116 adapted to carry a plurality of optical filters118 around its perimeter. The filter select wheel 116 is capable ofselectively positioning one of the plurality of optical filters 118 tointersect light emitted from a sample within the cavity interior 44. Thewheel 116 is rotatably mounted at its center to a mounting bracket 120attached to upper housing 16. The filter wheel 116 is mounted off-centerfrom the lens 100 such that the individual filters 118 can each berotated into position to intersect light emitted from the sample beforereaching the camera lens 100. The filter wheel 116 has a groove alongits perimeter edge in which a toothed belt 122 is seated. The toothedbelt 122 is also engaged with a drive wheel 124 on a filter wheel motor126. The filter wheel motor 126 is in electrical communication with theelectrical components 56 and controlled by a processor included incomputer 28. The plurality of optical filters 118 carried by the filterwheel 116 may include any of a variety of optical filters forfacilitating image capture such as a neutral density filter for brightsamples, one or more wavelength cutoff filters for restricting specificwavelengths, a fluorescent filter for fluorescence applications in whichthe excitation light differs from the detected light, etc.

In another embodiment, the filter select device 117 comprises a twofilter wheel 116 system. In this case, the filter select device 117includes a first optical filter select wheel 116 and a second opticalfilter select wheel 116, both of which are rotatably mounted in parallelat their center to the mounting bracket 120 attached to upper housing16. The first filter select wheel 116 is adapted to position a first setof optical filters included in the plurality of optical filters. Thesecond filter select wheel 116 is adapted to position a second set ofoptical filters included in the plurality of optical filters. The filterselect device 117 may then selectively position a combination of opticalfilters from the first and second wheels such that light emitted fromthe sample must pass through two optical filters. In a specificembodiment, the first and second filter select wheels 116 are eachadapted to carry seven optical filters. In another specific embodiment,the first and second filter select wheels 116 are each adapted to carrytwelve optical filters.

The F-stop motor 106, lens focus motor 114, and filter wheel motor 126are each stepper motors capable of suitable position control of theirrespective components. By way of example, a model number SST 39D 1010(1.8 deg/step, 4.3V, 0.85 A), manufactured by Shinano Kenshi Co., Ltd,Japan, is suitable for use with any of the motors 106, 114 and 126. Asshown in FIG. 12, each of the motors 106, 114 and 126 is in electricalcommunication with one or more electronic components 56 housed in drawer54 via wires 134. The electronic components 56 are, in turn, incommunication with the computer 28 where the motors 106, 114 and 126 maybe controlled by appropriate software and/or by user input.

The box 12 also includes a movable stage 58 on which the light-emittingsample is supported. The movable stage 58 is capable of linear,reciprocal movement between the partition 52 and the top enclosure panel41, and may be retained at any position therebetween for image capture.Thus, the moveable stage 58 has a multiple vertical positions in theinterior cavity having the substantially same horizontal position. Asshown in FIG. 12, the movable stage 58 has a threaded bore that isoperably engaged with a worm gear 136. The worm gear 136 providesvertical translation of the moveable stage 58. A motor 138 (e.g., modelnumber SST 42D 2120 from Shinano Kenshi Co. (1.8 deg/step, 3.7V, 1.2 A))drives the worm gear 136 to move the stage 58 up and down along a pairof guides 140. In another embodiment, the stage 58 is driven verticallyusing a belt driven system that provides a faster response than the wormgear 136.

In one embodiment, the movable stage 58 supports a removable verticalwall placed on the upper surface of the movable stage 58. The verticalwall acts as a light shield that prevents light emitting from a sampleto translate horizontally across the stage 58 surface to a portion ofthe moveable stage 58 that does not support the sample. For imagecapture of multiple samples in which one sample producing excessivelight, the vertical wall may then be useful in preventing the excessivelight from this sample to undesirably affect imaging of an adjacentsample.

Also associated with the moveable stage 58 is a position sensor 142. Theposition sensor 142 communicates with the computer 28 and provides aread-out which may be used in position control of the stage 58. In thiscase, the position sensor 142 includes a string or thin string 144having one end attached to the moveable stage 58 while the other end isattached to a take-up reel in the position sensor 142. Based on theamount of string 144 wound on the reel and the total length of thestring 144, the position sensor 142 is able to determine the length ofstring between the stage 58 and the sensor 142. This length is thenconverted into the height of the moveable stage 58 relative to partition52., e.g., by using a look-up table in computer 28 to carry out theconversion. In another embodiment, the position sensor is a laserpositioned in the interior cavity 44 to intercept the moveable stage 58at a starting vertical position. The laser may then be used to calibratethe position of the moveable stage 58 to the starting vertical position.

In many imaging applications, the low intensity light source may beembodied in any of a variety of light-emitting animals containinglight-emitting molecules, such as various mammalian subjects containingluciferase expressing cells. Often, thermoregulatory functioning of theanimal has been compromised to facilitate analysis or image capture,e.g., many laboratory mice are genetically hairless or the mice aresedated during imaging to minimize any movement that may compromiseimaging. Correspondingly, in one embodiment of the present invention,the system 10 includes a temperature control element 132, e.g., a heateror cooler, configured to control the temperature of one of the sampleand the interior cavity 44, or both. For example, while imaging mammalsor mammalian cells, it is often desirable to maintain the specimens ator near 37 degrees Celsius. In these cases, the imaging system 10 keepsthe stage 58 and sample warm by heat provided by the temperature controlelement 132 at or near 37 degrees Celsius.

In the embodiment shown in FIG. 11, the temperature control element 132is provided by a heating blanket placed on top of stage 58. In anotherembodiment, as shown in FIGS. 12 and 13A, the temperature-adjustingelement 132 is a thermal sheet 160 for controlling the temperature ofthe sample (such as M2436 1234 24V 35 W as provided by Instrument Labsof Los Angeles, Calif.) that is fixed, e.g. glued. into a cut-awayportion of stage 58. The temperature-adjusting element 132 includesheating element lead 162 which supplies the power for heating element160 and extends from thermal sheet 160 and is in electricalcommunication with electronic components 56 housed in drawer 54.Together, the heating element lead 162, electronic components 56 andcomputer 28 allow temperature and heat control of thetemperature-adjusting element 132.

As mentioned before, it is often desirable to sedate a light-emittinganimal during imaging to minimize any movement that may affect imaging.In many cases, an anesthetizing gas is supplied to the animal to keepthe animal sedated for an extended period of time. In these cases, theimaging system 10 includes a gas delivery system 220 detachably mountedon the moveable stage 58 to deliver a gas to the sample.

In the embodiment shown in FIGS. 13B-C, the gas delivery system 220comprises a gas manifold 222 detachably coupled to the moveable stage58. The gas manifold 222 includes a plurality of interfaces 224. Eachinterface 224 is adapted to provide a gas to a sample resting on themoveable stage 58. In a specific embodiment, the gas manifold 222comprises five interfaces 224 that are each funnel shaped to accommodatedifferent sized samples. The gas manifold 222 may be screwed using bolts227 or otherwise fixed to the stage 58 in a detachable manner. A valve225 associated with each interface 224 controls gas flow to the samplethrough its respective interface. A tube 226 supplies gas to the gasmanifold 222 and extends from outside the box 12. To reach a sample, gassupplied from the tube 226 flows through a channel 229 to an interface224 that accommodates the sample. In one embodiment, the tube 226includes a distal end that is open to the environment outside the box12. In this case, the tube 226 is substantially long and extends along alarge distance in the cavity interior 44 with numerous turns. The tube226 also has a large length to cross sectional area and includesnon-reflective surfaces that minimize light passage through the tube226. As a result, the end of the tube 226 inside the cavity interior 44emits substantially no light within the cavity interior 44. In aspecific embodiment, the tube 226 has a diameter of ¼″ ID to ⅜″ ODinches and a length of about 85 to about 90 inches and is made of blackPVC. A second tube 228 may also be included as a gas outlet.

As light retained in any elements inside the box 12 may undesirablyaffect subsequent luminescent image capture, the manifold 222 comprisesa non-reflective surface and a non-light retaining material. In aspecific embodiment, the gas manifold 222 is made of glass that does notretain light introduced to the manifold 222 when the door 18 is open. Inanother embodiment, the gas manifold 222 is autoclavable. Theautoclavable gas manifold 222 allows simple sterilization andcontaminants to easily be removed from the gas manifold 222. Forexample, the gas manifold 222 may be autoclaved by subjecting themanifold 222 to high temperatures and pressures, e.g., up to about 60psi and about 130 degrees Celsius. Together, the tube 226, gas manifold222, and interfaces 224 gas supply to one or more samples in the cavityinterior 44 from a gas source outside the box 12. A knob may also beincluded on an outside surface of the box 12 to control gas supplythrough the tube 226.

In accordance with another aspect of the present invention, a lightsource is provided in the interior cavity 44 for illuminating the sampleor specimen in the imaging box 12. The light source may be continuouslyilluminated or flashed while capturing photographic images of the sampleand is turned off for capturing luminescence images. As illustrated inFIG. 14A, the light source comprises a ring of low-wattage lights 128mounted on the bottom surface of a partition 130 positioned around thecamera lens 100. The partition 130 is positioned below the othercomponents housed in the top area of the box and separates the upperportion of the box 12 from the cavity 44. The partition 130 is attachedto at least one side of the box 12 and also includes a hole 129 forcamera 100 visibility. In another embodiment, as illustrated in FIG.14B, the light source comprises four pairs of white-light emittingdiodes (LEDs) 131, one pair mounted in each of the corners of partition130 around the camera lens 100. One advantage of using such LEDs is thatthe spectral emission thereof may be contained to visible light whileexcluding infrared light. Wires (not shown) may extend from the lightlow-wattage lights 128 to the electronic components 56 and computer 28to allow light levels to be controlled externally through the computer28.

The light source may also include a fiber optic cable. In a specificembodiment, the fiber optic cable has a first end located in theinterior cavity 44 and a second end located outside the box 12. Thefirst end may be used to illuminate the sample while the second endextends outside the box 12 to a light source that provides the light tothe optic cable. Within the cavity interior 44, the fiber optic cablemay be contained in a flexible “snake-like” housing that maintains adesired position of the first end as provided by a user. This allows theuser to flexibly position the first end relatively close to the samplefor illumination in a particular photographic capture. A filter may alsobe used with the fiber optic light source to provide a particularlighting effect. In a specific embodiment, the fiber optic light sourceis used to make various samples fluoresce and the filter is used toselect the wavelength of light to excite the sample. In this case,filters in the filter select device 117 of FIG. 9 allow a camera to onlyreceive selected light that is fluorescing in the sample. When thesecond end is located outside the box 12, the imaging box 12 includes ahole that allows said fiber optic cable to pass therethrough. When theoptic cable is not in use, the hole may be suitably plugged to preventlight from entering the box. In another embodiment, there is a break inthe fiber optic cable at the box 12 wall that allows a user to removeeither the outside or inside fiber and cap the remaining end off tominimize light leakage to the inside of the box 12.

To provide additional light protection for the interior cavity 44, oneor more walls forming the cavity 44 may be light sealed. For example, itmay be advantageous to light seal the partition 52 and/or the topenclosure panel 41 (FIG. 11).

FIG. 1D is a cross-sectional view of a conventional seal 5 that may beused for preventing light from entering an enclosure between twoadjacent walls 6 and 7 of the enclosure housing. The seal 5 is formedbetween two opposed surfaces 6 a and 7 a of the walls 6 and 7 to bejoined. Together, the opposed surfaces 6 and 7 form a channel 8 forreceipt of an o-ring 9. Only one of the surfaces, surface 6 a, isrecessed for the channel 8, while the other surface 7 a is flat.

FIG. 15 shows a light seal 164 in accordance with one embodiment of thepresent invention. Light seal 164 is employed, for example, in theassembly of upper housing 16, and at the contact between upper housing16 and top plate 103 (see FIG. 11 for both cases) and is used forpreventing light from entering the cavity 44 from the top portion of thebox 12. Light seal 164 includes a gasket 166 which is composed ofcompressible material, such as a rubber o-ring, and two opposingchannels 168 a and 168 b, each located in one of two substantiallyplanar surfaces 170 a and 170 b. The surface 170 a, defining the firstchannel 168 a, and the second surface 170 b, defining the second channel168 b, are configured such that the channels are aligned at leastpartially with each other. The compressible gasket 166 is disposed inthe channels 168 a and 168 b and configured to contact opposing edges ofthe channels 168 a and 168 b when the surfaces 170 a and 170 b arepositioned in opposed relationship to one another. In addition, thegasket 166 and channels 168 a and 168 b may also be configured such thatthe gasket 166 is positioned at the intersecting edges between thechannels 168 a and 168 b and the corresponding surfaces 170 a and 170 b.

In accordance with this aspect of the present invention, this light seal164 is a more effective light barrier than the conventional seal 5 ofFIG. 1D. In the conventional seal, if there is a slight gap between theseal 9 and the surface 7 a such as an inconsistency in either of thesurfaces 6 a and 7 a along the o-ring 9 length, light can pass betweenpoints C and D with virtually no change in direction. In contrast, whenthere is an imperfection in the sealing of the o-ring 166 against one ofthe flat surfaces in FIG. 15, entering light would require multipledirection changes to pass between points A and B. Accordingly, the lightseal 164 reduces the amount of light entering the cavity 44 due to anydefects in the light seal 164 along its length.

Referring now to FIG. 16, there is shown a top perspective view ofdrawer 54 and electronic components 56 housed therein. As previouslynoted, these components interface with the computer 28 and are used tocontrol the various motors and other components of the imaging system10. A 3 V power supply 137 provides electrical power to the variousactive components in the drawer 54. A motor control board 146 has fourmotor controllers 148, 150, 152, 154 mounted thereon. The motorcontrollers 148, 150, 152, 154 are in communication with each of theF-stop motor 106, lens focus motor 114, and filter wheel motor 126 andstage motor 138, respectively, via wires 134. Each motor controllerinterfaces, via cable 34, with the computer 28 where the motorcontrollers and motors may be controlled by appropriate software runningon the computer and user input. Drawer 54 also houses a data acquisitionboard (DAB) 156. On the face of the drawer is a knob 155 which is incommunication with light source 128 and allows the user to manually tocontrol the light intensity in the interior cavity 44. Also on thedrawer face is a heater controller 158 which is in communication withheating element lead 162 to control and display its temperature.

B. Comparison of the Imaging System of the Present Invention with aConventional Light Box

Tests were conducted to compare a conventional light box—model numberA4178 as manufactured by Hamamatsu Photonic Systems of Bellerica,Mass.—and an imaging box in accordance with one embodiment of thepresent invention. Each box was tested under substantially identicalconditions. For the Hamamatsu box, a camera was installed on andoperably connected with image capturing equipment. A piece of whitepaper was placed inside the box, approximately 12″ away from the frontof the camera lens, to serve as a reflective sample. The door of the boxwas closed, and an image was acquired with the exterior room lights on.The room lights were then turned off, and a second image was acquired.The total amount of light acquired under the two conditions wascompared. The camera was then transferred to an imaging box of thepresent invention, and images were acquired under the same conditions.

The testing showed that approximately 130% to 140% more external lightentered the Hamamatsu box with the exterior lights on than with themoff. In comparison, the imaging box of the present invention measuredonly about a 3% increase in the amount of light entering the box withthe exterior lights on as compared with the exterior lights off.

II. Operation of the Imaging System of the Present Invention

The present invention may be employed in a wide variety of imagingapplications. Generally, the present invention may be applied with anynon-invasive methods and compositions for detecting, localizing andtracking light-emitting entities and biological events in a mammaliansubject. For example, the imaging system 10 may be implemented withintensified Charge-Coupled Device (CCD) cameras to detect thelocalization of light-producing cells (e.g., certain bacteria or tumorcells made bioluminescent by transforming them with luciferase DNAconstructs) inside of living animals, such as mice. In suchapplications, an animal containing the bioluminescent cells is placedinside of the specimen chamber, and within the field of a photodetectiondevice, such as an intensified CCD camera. The camera is then activatedto detect the emitted photons. The photon signal may then be used toconstruct a luminescent image of photon emission. The luminescent imageis constructed without using light sources other than the luminescencefrom the sample itself. This luminescence is recorded as a function ofposition to produce the luminescence image. The photographic image mayalso be taken of the same sample to aid in position visualization of theluminescent image. One approach to generating such compositephotographic/luminescence images is described in U.S. Pat. No. 5,650,135issued to Contag et al. on Jul. 22, 1997. The entire disclosure of thatpatent is incorporated herein by reference for all purposes.

Turning now to FIG. 17, a flow chart illustrates a method of capturingphotographic and luminescent images using the imaging system 10 inaccordance with of the invention. The method begins by placing a sampleor specimen to be assayed for light emission on the stage in the imagingbox 12 (202). The imaging box 12 and associated image components arethen prepared for capturing a photographic image of the sample (204).The preparation may include launching imaging and acquisition software(e.g., “LivingImage”, Xenogen Corporation, Alameda, Calif.) on thecomputer 28 and initializing the camera 20. Further preparations mayinclude selecting the desired stage 58 position, closing the door 12,activating the photographic capture option in the software, and turningon the lights (e.g., lights 128 or 132) in the box. Preparations mayfurther include focusing the lens 100, selectively positioning anappropriate lens filter 118, setting the f-stop, etc.

The photographic image is then captured (206). In one embodiment, a“live mode” is used during photographic imaging of the sample to observethe sample in real time. The live mode includes a sequence ofphotographic images taken frequently enough to simulate live video. Uponcompletion of photographic capture, the photographic image data aretransferred to an image processing unit 26 and/or computer system 28(208). These may be used to manipulate and store the photographic imagedata as well as process the data for display on computer monitor 38.

Subsequently, imaging box 12 and associated image components areprepared for luminescence image capture (210). Such preparation mayinclude, for example, selecting luminescent exposure time and binninglevel using the computer 28, and turning off the lights in the cavity44. The CCD camera 20 then captures (212) the luminescence image over aset period of time (up to several minutes). The luminescence image dataare transferred to the image processing unit 26 and/or computer 28(214), which may be used to manipulate and store the luminescence imagedata as well as process it for display on the computer display 38 (step214). The manipulation may also include overlaying the luminescent imagewith the photographic image and displaying the two images together as an“overlay” image, with the luminescence data typically shown inpseudocolor to show intensity. This overlay image may then be the basisfor user analysis (216). At this point, the user has the components of adigital overlay image (including the luminescence image and thephotographic image) stored in the computer 28. The information containedin these image may be analyzed and manipulated as desired.

Based on the foregoing, it should be readily apparent to those skilledin the art that a substantially improved imaging box for imaging lowintensity light sources has been disclosed. The improved sealingarrangements and door securing designs of the present invention providesubstantially more light-tight enclosures than have been previouslyavailable. Various additional improved features of an imaging box havealso been disclosed, including a novel automated filter select device,automated camera focusing, f-stop adjustment, automated stage height,internal illumination and sample temperature control. Moreover, it willbe apparent to those skilled in the art in light of the foregoingdisclosure that further alternatives, modifications and variations arepossible. For example, imaging systems in accordance with the presentinvention may not necessarily include all the improvements andembodiment disclosed herein and may include any one or more of the abovedescribed embodiments. In addition, the present invention is suitablefor other imaging applications and may be tailored correspondingly. Byway of example, the present invention may be adapted for analysis ofhigh detail in-vivo applications and thus may include zoom tools for thecamera 20 and controlling computer 28. Also, the various properties andcharacteristics of the compressible material 62 are by way of exampleonly and other materials and variations may be suitable. Althoughvarious details have been omitted for brevity's sake, obvious designalternatives may be implemented. Therefore, the present examples are tobe considered as illustrative and not restrictive, and the invention isnot to be limited to the details given herein, but may be modifiedwithin the scope of the appended claims.

1. An imaging system for capturing an image of a sample, the imagingsystem comprising: an imaging box including: a body including aninterior cavity for receiving the sample, and having a front portiondefining an opening into said cavity, said body further including a viewhole enabling viewing of the sample; and a door having a rear portion,said door movable between an opened condition, enabling access to theinterior cavity through the cavity opening, and a closed condition,positioning said rear portion substantially adjacent the body frontportion to prevent access through the cavity opening; and an opticalfilter select device configured to selectively position one of aplurality of optical filters between the sample and the view hole tointersect light from the sample.
 2. The imaging system of claim 1,wherein the plurality of optical filters includes at least one of aneutral density filter, a wavelength cutoff filter, and a fluorescentfilter.
 3. The imaging system of claim 1, wherein the optical filterselect device is configured to rotate the plurality of optical filtersto selectively provide one of the plurality of optical filters tointersect light from the sample.
 4. The imaging system of claim 3,wherein the optical filter select device further includes a first wheeladapted to position a first set of optical filters included in theplurality of optical filters, said first wheel being rotatably coupledto the imaging box.
 5. The imaging system of claim 4, wherein the filterselect device further includes a second wheel adapted to position asecond set of optical filters included in the plurality of opticalfilters, said second wheel being rotatably coupled to the imaging box.6. The imaging system of claim 1, further including: a light sourceemitting light into the interior cavity.
 7. The imaging system of claim6, wherein the light source comprises a fiber optic cable having a firstend located in the interior cavity and a second end located outside thebox.
 8. The imaging system of claim 6, wherein the light sourcecomprises a ring of lights positioned around said optical filter selectdevice.
 9. An imaging system for capturing an image of a sample, theimaging system comprising: an imaging box having: a body including aninterior cavity for receiving the sample, and having a front walldefining an opening into said cavity; and a door having a rear wall andan exterior face, said door movable between an opened condition,enabling access to the interior cavity through the cavity opening, and aclosed condition, positioning said rear wall substantially adjacent thebody front wall to prevent access through the cavity opening; and anoptical filter select device adapted to carry a plurality of opticalfilters, the filter select device capable of selectively positioning oneof the plurality of optical filters to intersect light from the sample.10. The imaging system of claim 9, further including: a processor inelectrical communication with the optical filter select device, saidprocessor configured to provide output for controlling the position ofsaid optical filter select device.
 11. The imaging system of claim 9,wherein the plurality of optical filters includes one of a neutraldensity filter, a wavelength cutoff filter, and a fluorescent filter.12. The imaging system of claim 9, wherein the optical filter selectdevice rotates the plurality of optical filters to selectively provideone of the plurality of optical filters to intersect light emitted fromthe sample.
 13. The imaging system of claim 12, wherein the opticalfilter select device further includes a first wheel adapted to positiona first set of optical filters included in the plurality of opticalfilters, said first wheel being rotatably coupled to the imaging box.14. The imaging system of claim 13, wherein the filter select devicefurther includes a second wheel adapted to position a second set ofoptical filters included in the plurality of optical filters, saidsecond wheel being rotatably coupled to the imaging box.
 15. The imagingsystem of claim 9, further including: a light source in the interiorcavity.
 16. The imaging system of claim 15, wherein the light sourcecomprises a fiber optic cable having a first end located in the interiorcavity and a second end located outside the box.
 17. The imaging systemof claim 16, wherein said imaging box includes a hole that allows saidfiber optic cable to pass therethrough.
 18. The imaging system of claim15, wherein the light source comprises a ring of lights positionedaround said optical filter select device.
 19. The imaging system ofclaim 18, wherein the light source comprises a plurality of lightemitting diodes.